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US 11,203,077 B2Granted
Apparatus for controlling AC weld current by means of an arc igniter
OwnerGordon R. Hankainventor
Life of this patent
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Abstract
My invention is an improvement to a welding arc igniter. My invention periodically disables the arc igniter for one or more AC half-cycles. When the igniter skips an AC half-cycle, the welding arc may not ignite, so average weld heat is reduced. AC weld heat can be adjusted in real time, by varying the fraction of AC half-cycles that are skipped. AC polarity balance can be adjusted in real time, by preferentially skipping the electrode-positive or electrode-negative half-cycles.
Claims4
A welding arc controller, comprising an arc igniter, a pulse-width modulator, and a user control;
- wherein said arc igniter generates an absolute peak voltage of at least 500 volts but less than 100,000 volts in a weld-current conductor of at least 100 amps capacity;
- said amps capacity and peak voltage are measured at 20% duty cycle;
- said arc igniter is enabled by said pulse-width modulator;
- said pulse-width modulator is configured to ignite some AC weld-current half-cycles but not others, according to an ignition schedule;
- said AC half-cycle is considered ignited when said arc igniter is enabled during an effective ignition period;
- said arc igniter is considered enabled if it raises absolute weld voltage above 500 volts;
- said AC half-cycle is the time between the periodic zero crossings of the AC weld voltage;
- said effective ignition period is the first three fourths of said AC half-cycle;
- said pulse-width modulator is configured to produce at least three ignition schedules;
- said ignition schedule may be specified directly or by one or more statistical summary measures;
- said ignition schedule is selected by said user control.
8 more elements
Dependencies are inferred from the claim text.